Hello everyone,

I'm trying to look at Mumford's Paper, 'The Pathologies of Modular Surfaces'. (link: http://www.dam.brown.edu/people/mumford/Papers/DigitizedAlgGeomPapers--ForNon-CommercialUse/61b--Path1.pdf)

On page 341, section II. he says a certain surface can be constructed as the join of 3 graphs $E_0 \rightarrow \mathbb{P}^1$-what is the join of graphs?

Cheers!

Hello everyone,

I'm trying to look at Mumford's Paper, The Pathologies of Modular Surfaces.

On page 341, section II he says a certain surface can be constructed as the join of 3 graphs $E_0 \rightarrow \mathbb{P}^1$. What is the join of graphs?

Cheers!